Field
The present disclosure relates to systems and methods for determining whether a transmission downshift of a vehicle towing a trailer is desirable due to a downslope and for alerting the driver of a desirable downshift and/or automatically downshifting the transmission when desirable.
Description of the Related Art
Vehicles can occasionally accelerate when traveling along a downslope (i.e., on a downhill portion of road) due to gravity. Whether the vehicle accelerates and the rate of acceleration of the vehicle can be affected by numerous factors such as a grade (i.e., slope) of the downslope, a length of the downslope and a weight of the vehicle. Many large trucks are thus more prone to accelerate while traveling along a downslope than personal vehicles (such as cars, SUVs and pickup trucks) due to the difference in weight. However, vehicle load can significantly increase if a trailer is hitched to the vehicle. Thus, vehicles hitched to trailers are more susceptible to undesired acceleration while traveling downhill.
When a vehicle begins to accelerate while traveling along a downslope, the vehicle must brake in order to maintain a constant speed. If the downslope is relatively long and/or has a relatively large grade, a relatively large amount of braking may need to be applied. The relatively large amount of braking can be undesirable because brakes can overheat after a sufficient amount of braking. Functionality and remaining use of the brakes may decrease as the brakes continue to overheat.
Engine braking (i.e., reducing the gear of the vehicle to slow down) can be used to reduce acceleration along the downgrade. Some experienced drivers will thus downshift when they are aware of an upcoming downslope, particularly if the downslope has a relatively large grade and length. However, not all downslopes are indicated by a sign, and it may be undesirable to downshift while traveling downhill due to potential torque disturbances.
The brakes may also overheat when used to decelerate a vehicle having a relatively large load as the vehicle slows down to follow a curve or make a turn.
Thus, there is a need for systems and methods for determining the location of downslopes and turns and for alerting the driver to an upcoming downslope and/or for automatically shifting the transmission to a higher gear ratio in response to an upcoming downslope.